Brake drum lathe



Dec. 29, 1953 H. B. BARRETT BRAKE DRUM LATHE 4 Sheets-Sheet 1 Filed Aug. 28, 1950 INVENTOR. HARRY B. BARRETT BY Dec. 29, 1953 H. B. BARRETT BRAKE DRUM LATHE 4 Sheets-Sheet 2 Filed Aug. 28, 1950 \Q m & m & \R m I. I]. I 3 m k fi tlili \.J r a I I 1 m km N H I M l I \m W g g a \m M I! Q Q 0 w. N N UE INVENTOR. HARRY B. BARRETT Dec. 29, 1953 Filed Aug. 28, 1950 H. B. BARRETT 2,663,975

BRAKE DRUM LATHE 4 Sheets-Sheet 3 INVENTOR.

HARRY B. BARRETT Dec. 29, 1953 H. B. BARRETT ,663,

BRAKE DRUM LATHE Filed Aug. 28, 1950 4 Sheets-Sheet 4 Patented Dec. 29, 1953 UNETED STATES Z tt375 v FATENT OFFICE BRAKE DRUM LATHE Harry B. Barrett, St. Louis, Mb. Application August 28, 1950, seriainoiisus r V 3 claims. (01. 51 37) This invention. relates in general to machine tools and, more particularly, to certain new and useful improvements in lathe-type turning machines adapted for use in the finishing and truing of brake drums and the like, although the same is not necessarily limited to such particular use.

The primary object of the present invention is to provide a lathe of the type stated which is provided with motor cut-off means whereby the machine will be stopped upon completion of the tool feeding stroke, which means may be adjusted for the particular operation.

A further object of the present invention is to provide a lathe of the type stated which integrally contains an auxiliary power take-01f which provides a suitable mounting for tools such as drills, grinding wheels, andthe like whereby the lathe becomes a combination machine capable of use in amultiplicity of brake relining operations, such as drilling, honing, reaming, tool-resharpening, and the like.

It is an additional object of the present invention to provide a lathe of the type stated which is simple, durable and economical in construction, which is accurate and precise inmetal turning operation and which is adaptable for awide variety of work such as turning, grinding, truing,

and work surfacing on various types and sizes of Y brake drums.

With the above and other obiects in View, my invention resides in the: novel features of form, construction; arrangement, and combination of parts presently described and pointed out in the claims.

In the accompanying drawings (four sheets)-- Figure 1 is a front view of a brake drum lathe constructed in accordance with and embodying the present" invention;

Figure 2 is a transverse sectional view taken along line 2-2 of Figure 1;

Figure 3' is an elevational view with part of the housing wall cut away;

Figure 4 is a transverse sectional: view taken along line 4i of Figure 1; t

Figures 5 and 6 are transverse sectional views taken along lines 5 5 and 6-45; respectively, of Figure 3;

Figures F and; 8 are.- fragmentarysectional views the changers in: slow and: fast positionrespectively;

Figure 9' is a transverse. sectional?- view taken along lined-91 of Figure 1;

Figure 10 is a fragmentary'top plan view showing the carriage as adapted for supporting; a

grinding wheel;

Figurell is an endview thereof and Figure 12 is a transversesectional view taken along line I 2 I2 of'Figure 10.

Referring now by'reference characters to the drawings which illustrate a preferred embodiment of the present invention, A designates a brake drum lathe having a base plate I upon which is suitably mounted a longitudinally extending housing 2: having at one end a side wall 3- and at its opposed end a partition forming a common wall with an integrally cast, enlarged compartment 5. To permit access to the interior of the compartment 5 an end plate 8 is removably mounted by bolts 1 extending through registering apertures provided in the margins of the compartment 5. Disposed to the rear of, and in elevated relation to, the base plate I is'a platform 8 supported by a bar 9 which is secured at its inner end tothe housing 2'. Bolted upon the platform 8' is a conventional type electric motor it and provided upon the platform 8 for vibration dampening purposes when the motor I!) is actuated. is an arm i! extending upwardly through the platform 8 and having a lower bent end suitably fitted in the plate l, with a compression' spring i2 disposed about the vertical portion of the rod H and extending through the platform 8 so that the'latter is, in effect, engaged in one of the central convolutionsof the spring i2 and is resiliently suspended therein. At its upper end the spring I! bears against a wing nut Hi threadedly'mounted upon the upper end of the rod I! for adjusting the tension of the spring- [-2 as requisite for absorbing the vibrations caused by the selected speed of the motor Ill.

Projecting from the motor ll] is adrive shaft M whichextends into the lower portion of a generally cylindrically shaped housing I5 of twopart construction; having a stationary section l 6, integrally formed with; and tothe rear of, the compartment. 5 and a removablev section I? attached to thesection. Iii-by means of a latch 1-8. Splined or. otherwise suitably mounted upon the projecting end of the shaft it isa series of, preferably three, graduated cone pulleys I 8, 2'0, 2!, having provided for disposition thereon an endlessbelt 2-2; the upper portion of which is trained about the selected one cat a series of corresponding cone pulleys 23;, 24, 25, in respective alignment-withthe cone pulleys i9, 2t, 2!, and being splined. or otherwise mounted on one end of a transmission shaft 26. It is, to be noted that the cone-pulleys L9, 2e, 2!, and; 23, 24, 25, are paired? in the conventional manner to provide a range of" three speeds of rotation for the trans,

mission shaft 25. Said shaft 26 is journaled in ball bearings 21, 28, and thrust bearings 29, 30, disposed in aligned apertures 3!, 32, respectively, in the rear and forward walls l, respectively, of the compartment 5. At its forward end the shaft is diametrally reduced and projects outwardly beyond the forward face of thecompartment 5 to provide an auxiliary power take-off 33 for such purposes as a mechanic may elect, as for supporting a drill, milling cutter, and the like.

Keyed centrally upon the shaft 26 within the compartment 5, is a worm 34 in meshing engagement with the worm gear 35 mounted upon a longitudinally extending spindle 36 which extends through the housing 2 being journaled in pairs of thrust bearings 31. 38, provided in the side wall 3 and the partition wall 4, respectively. The spindle 36 projects at one end substantially beyond the side wall 3, projecting end portion being diametrallv reduced as at 9 or supporting the work, such as an automotive brake drum, and is threaded at its end extremity for receiving a work-retaining collar (not shown). At its other end the spindle 36 is threaded for receiving a collar All} and is diametrally reduced, as at 4!, for supporting a worm 42 keyed or otherwise mounted thereon, with its end extremity bearin ed n the plate 6.

In meshing engagement with the worm 42 is a horizontally d sposed worm gear 43 suitably mounted upon the upper end of a vertically extending jack shaft 44, on the lower end of which is disposed a bevel gear 45 for engagement with a pinion 46 mounte upon a longitudinally extending feed shaft 41 .iournaled at its ends in aligned bearings 41', 41", in the end plate 8 and the partition wall 4 of the compartment 5. respectively. Presented in forwardly spaced relation, and parallel to, the feed shaft 41 is the base portion of a lead screw 48 which is iournaled in and extends throu h a partition wall 4. with proiecting portions of the screw 48 passing longitudinally along, and forwardly of, the outer face of the housing 2 w thin an arcuate recess 49 formed therein. At its other end the lead screw 48 is bearin ed in, and proiects through, the end plate 6 of the compartment 5, havin mounted upon its projecting end a hand wheel 50. It will be noted by reference to Figure 1 that the portion of the lead screw 48 which extends through the partition wall 4 is plain or unthreaded and that between such. plain portion and the ommencement of the threads, the lead screw 48 is undercut as at 48' for purposes presently more fully appearing.

Formed in the forward face of the compartment 5 is an outwardly bulging portion 5! having a vertically elongated aperture 52 provided therein. Disposed across the aperture 52 and suitably afiixed to the outer face of the compartment 5 is a plate 53 arcuately shaped in conformity with the radius of the portion 5! and having a central aperture 54 aligned with the aperture 52. About the vertical margins of the aperture 54 there are provided aligned pairs of recesses or notches 55, 5B, 51. Extending loosely through the aperture 54 is a gear shift lever 53 provided on its extended end with a snug fitting spring biased sleeve-like handle 59 which is diametrally reduced at its inner end for optional engagement in any selected pair of notches 55, 55, 5?. R-ockably mounte pon the unthreaded portion of the lead screw 48 is a change plate 60 integrally provided with a boss 6| which is threaded and tapped for receiving the inner threaded end of the lever 58. The change plate 60 forms an essential element of a change-gear transmission generally designated C. The change plate 61 is substantially V-shaped and at its apex is centered upon the lead screw 48 for rockable movement thereon and being pivotally attached at its lower end to one end of a link 82 which, at its other end, is pivotally attached to the lower end of a second V-shaped plate member 63 mounted upon the feed shaft 41 for pivotal movement thereon.

The change gears C comprise horizontally aligned gear clusters 64, 65, disposed upon the feed shaft 4'1 and the base portion of the lead screw 48, respectively. The gear cluster 54 includes a small diameter driving gear 66 in constant meshing engagement with an intermediate or idler gear 61 of relatively increased diameter and disposed for rotation upon a bolt 68 engaged in the upper portion of the plate 63. Keyed upon the feed shaft 47 on the side of the plate 63 opposite to the gear 68 is a large diameter driving gear 69. The gear cluster 65 on the lead screw t8 correspondingly includes a large diameter pinion or driven gear 16 and a small diameter pinion 'H keyed upon the lead screw 48 on opposite sides of the plate cc and in alignment with the driving gears 65, 69, respectively. The pinion "H is in meshing engagement with an intermediate or idler gear 12 rotatably mounted upon a bolt 13 threadedly engaged in the upper portion of the change plate 66. As may be seen in Figure 6 the idler gear '12 is in laterally spaced relation to the idler gear 61 of the cluster 84. Thus, by operation of the lever 63, the change plate 60 may be swung to effect gear ratios for imparting either a relatively fast or slow speed of rotation to the lead screw 48. Referring now to Figure 8, it will be seen that when the lever 59 is in its uppermost position, within the notches 51, the idler gear '12 will be shifted into engagement with the large driving gear 69, whereby the small diameter pinion H is brought into train so that a speed increase is accomplished, causing the lead screw 48 to rotate at a relatively fast rate. As shown in Figure 7, with the lever 55 in its lowermost position, as engaged within the notches 55, the idler gear 12 will be shifted out of engagement and the intermediate gear 61 will have been swung into engagement with the large diameter pinion 10, which is thereby brought into train with the small driving gear 66 to cause a speed reduction whereby the lead screw 48 will rotate at a relatively slow speed. When the lever 58 is moved into its central position, within the notches 55 the change plate 68 will be pivoted so as to break engagement between the gear clusters 54, 65, whereby rotation of the lead screw 48 may be effected by manual operation of the hand wheel 50.

Integrally formed on the forward face of the housing 2 and extending longitudinally therealong is a dovetail slide-track 14 having its ways disposed on opposite sides of, and equidistant, to the recess 43. Mounted on the dovetail slidetrack 14 for translation therealong is a carriage it having a vertical web it centrally upon which is mounted, by means of a bolt Ti, a nut 13 projecting into the recess ti! and threadedly engaged upon the lead screw 48. Formed with the vertical web Hi are forwardly projecting side plates i9, 39, which at their upper ends are integral with a transverse web 8!, which is provided on its upper surface with a transversely extending dovetail slide 82, for engagement with slide 83: is provided with a depending skirtportion 84 upon the outer face of which is suitably mounted across feed knob 85 operatively' se curedto one end of'a cross feed screw 852 thread-- ed-ly engaged in a nut 8"? supported with-in a bearing 88 integrally formed with and depending from theunder face of the transverse web ill. By operationof the ci 'oslef'eed knob 85 the slide 8&- may be translated" alongthe slide way 82 a direction normal to the axis of the spindle 3'6. Detachablymounted upon the upper face of the slide: 83 by a bolt 89 is a tool support Gil-haw ingan enlarged bore 91' for receiving the shank es of a tool-holder 93 and being provided with.

set screws 9% for maintaining thetool-holder 53' securelyin position. Mountedby ascrew 8i: theend of the-tool-holder 93 is atool 96, hav i'nga replaceable tip 1* as more fully described in my copending application Serial No. 1 56,2336, filed April 19, 1950. Integrally cast with the carriage l5, and in lateral relation to the side plate 85- isa vertical websection 9-? having at its lower' end, a forwardl y'presented sleeve 98, axially parallel to the lead screw 8, for receiving a tripping red as which is beveled at one end, as at I 68. Provided for rigidly maintaining the rod 93 within thesleeve' 98 in selected relative position therein, is a bolt it"! threaded in a v suitable aperture within the sleeve as; In align.-

rnentwi'th the axis of the: rod t9 and projecting from the forward faceof the compartment 5 in downwardly spaced relation to the lever 59 is a spring l'eaf type lever It? resting at its free end against the outer end of the plunger tilt of a conventional electric: switch, as best seenin Fig. 3', the latter being conventionally connected to the motor l t-by suitableieads, In outward, laterally space relation to the lever It? and corn nested in series thereto is an indicating lamp 5 mounted within a suitable socket provided in the face of the compartment- 5. It will thus be seen. that upon: translation of the carriage it along the lead screw: 48 in the: direction toward thecompartment 5 the beveled end ltd oi the rod 9% will be brought into contact with the lever H12 and upon continued movement, the rod 99 will trip. the lever [G2 intoswitch-open position whereupon the motor l t will automaticall'y stop. It should be-noted' in this connection that the heel of the rod Ed abuts against the inner face of the side plate TS when the rod- 93 is pushedallthe way to theleft (reference being made to- Figure 1). In this latter position the right-ward distance between. the right hand face of the web 91 and. the. beveled: end i135 is: only slightly greater thanthe distance from theunderfor some reason, break. the electrical; circuit promptly: In such case the nutfilBs will; run, off" into the. undercut. 38!" and the: carriage "i=5; will cometa a. stop anyway. It is,,.oi. course, obvious that, when the carriage has stopped in this:man nor, the machine cane-be returned to operative condition by manually shutting off the switch andmanually pushing the carriage to the leth indicatinglamp s: which will be. illumihated during operation of. the motor will be simultaneously turned? ofii. As will; be. shown which; is threadedly' engaged at its lower end in a suitable: aperture irrthe: housing 2. (see Figure 42). The switch box: it is: connected by suitable leads passing through, the. conduit: let to the motor ii) and is provided. with a master" switch (not shown) having a tumbler Hit and a. socket t t-l to provide. an electrical output connection.

Projecting from the outer end of the. box: it;

is a socket-forming conduit its for receiving a worklamp we having a shade i It for optional energization by a switch button Hi to'provicle illumination directly to the. work surface being opera-ted upon; v

In usage, the. work, such an automotive brake drum is suitably positioned upon the end of the spindleflt. The particular tool 93', requisite for the? operationv indicated, is properly se cured in thetool holder $3. The gear shiftlever to is then moved into neutral position, within the notches to permit the operator to translate the carriage t5, by manual operation of. the hand. wheel 59, along the lead screw 58. in order to bring the tool into the: initialv or starting feed position with reference to the work. The cross feed: knob 85 is then turned to. move the cross slide 83 transversely to present the. tool 53 to: thework: in proximate: position forv the depth of cut to be taken. Ordinarily, when the. work is an automotivebrake drum the tool 93' will be presented to the inner face of the drum. The cross slide, 83, thus, provides a range. of adjustmentfor positioning the. tool 98 properly with brake drums of varying diameters, asby moving it-forwardl y for larger diameter drums and. rearwardly' for smaller diameter drums. Additionally, it is to be-noted thatwith various types. of work, other than brake drums, the, tool-holder 93 may be secured in the tool-support. St for presentingthe-tool 9t upon the exterior surfaces to. effect aso called dry run to determine the length of the'ieedstroke required for the operation. Upon determination of this distance, the operator may then adjust the tripping rod at longitudinally within the. sleevev its so that: upon completion of the feed stroke. the. beveled. end Ittiofi therod- 99: will contact. and trip the". toggle lever its forautomatical-ly shutting-cit the motor Ill. It is; of course; apparent that the rod. 52 Will be. so adjusted so as to permit a. slight time delay after the operation will have terminated to assume: that the toggle.- leyer m2 will not be prematurely trippedi With the longitudinal ad just'ment' of the rod et completed, the operator will manually return the carriage to the work and positionthe-tool 96 for the operation. gearshiit'lever 59will then be-shiited into either its upper or lower position to bring the change gears G intoproper meshing relationship for the lead screw 43 to feed the tool 55 to the work throughout the surface thereof to be machined. As described hereinabove, upon completion of the feed stroke the tripping rod 99 will trip the toggle lever IE2 to stop the motor It. By this automatic cut-off means, a mechanic could, during the operation of the lathe A, have his attention focused on some other matter with full assurance that the lathe A would stop upon completion of the job.

If desired, the tool-holder 99 may be removed from the carriage 15 by loosening the bolt 8G and there may be suitably affixed by a bolt H2 upon the upper transverse web 8i of the carriage 75 a casting H3 having an axial bore H5, for receiving a shaft H5 which projects at one of its ends beyond the adjacent end face of the casting H3 for supporting an abrasive grinding wheel HS disposed thereon. The shaft H5 is journaled in ball bearings il'i, H8, mounted in spaced, diametrally increased portions of 'the casting H3. At its opposite or inner end, the shaft H5 has mounted thereon a pull y H9 over which is trained a belt i253 connected at its other end to a pulley l2i disposed on the end of a driving shaft I22 of an auxiliary electric motor !23. Said motor l23 is integrally provided with a mounting plate i2 1 having lugs I25 for pivotal attachment by bolts i2 3 to a support plate i2? formed in the casting H3. Projecting through a threaded aperture l28 in the support plate I21 is an adjustment screw H29 for abutment against the mounting plate I25 to restrain the transmission of vibrations effected by the operation of the motor I23.

The motor I23 is connected by a conventional lead (not shown) to the socket it'll in the switch box for direct connection to the motor it. Thus, in operation, the carriage :75 may be translated along the lead screw 18 in order to present the grinding wheel H6 to the work surface. The tripping rod es may be adjusted in the manner hereinabove described to provide an automatic cut-off of the motor 16 upon completion of the feed stroke.

It should be understood that changes and modifications in the form, construction, arrangement, and combination of the several parts of the brake drum lathe may be made and sub stituted for those herein shown and described without departing from the nature and principle of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

l. A lathe for grinding brake drums and the like comprising a housing, a work-holding spindle journaled in and extending outwardly from the housing, a worm gear keyed upon the spindle within the housing, a cross-shaft journaled in the housing and extending transversely across the spindle in overlying relation to the worm gear, a worm keyed upon the cross-shaft and meshing with the worm gear, a prime mover mounted in the housing, motion transmitting means operatively connecting said cross-shaft with said prime mover, a carriage slidably mounted on the housing for movement therealong, a feed screw carried in the housing and engaged with the carriage, first and second spur gears rigidly mounted on the feed screw interiorly of the housing, a feed shaft journaled in the housing and positioned in spaced parallel relation to the feed screw, third and fourth spur gears rigidly mounted on the feed shaft, the first and third gears being positioned in edgewise alignment with each other and the second and fourth gears similarly being positioned in edgewise alignment with each other, a first crank-arm operatively mounted in the housing for rocking movement about an axis coincident with the center line of the feed screw, a second crank arm operatively mounted to the housing for rocking movement about an axis coincident with the center line of the feed shaft, a link pivotally connected at its ends to the first and second crank arms for causing the crank arms to rock simultaneously with each other, a first idler gear journaled upon the outer end of the first crank arm and being in toothed engagement with the first spur gear, said first idler gear being adapted upon swinging movement of the first crank arm to roll around the periphery of the first spur gear without interruption of its toothed connection with the first spur gear, a second idler gear journaled upon the outer end of the second crank arm and being in toothed engagement with the fourth spur gear, said first idler gear furthermore being adapted to swing around into toothed engagement with the third spur gear so as to effect driving connection between the first and third spur gears, said second idler gear being adapted to swing around into toothed engagement with the second spur gear so as to effect driving connection between the second and four spur gears, said first and second crank arms being so positioned in relation to each other that the second idler gear will be disconnected from the second spur gear when the first idler gear is drivingly connected to the third spur gear and so that the first idler gear will correspondingly be disconnected from the third spur gear when the second idler gear is drivingly connected to the second spur gear, and handle means operatively connected to said crank arms for permitting said crank arms to be manually swung to and fro.

A lathe for grinding brake drums and the like, as defined in claim 1, in which the crossshaft extends at one end outwardly through the housing, and is adapted at its outwardly projecting end for receiving an auxiliary tool.

3. A lathe for grinding brake drums and the like comprising a housing, a work-holding spindle operatively journaled in and projecting at one end from the housing, a carriage slidably mounted on the housing for movement in cu"- Wardly spaced parallel relation to the spindle,

'a tool mounted on the carriage, a feed screw journaled in the housing and threadedly engaged with the carriage for feeding a tool to the work, said feed screw being provided adjacent one end with an unthreaded portion along which the carriage will become disengaged, an electric motor drivingly engaged with the spindle, a boss formed on the carriage and having a horizontal aperture, the axis of which is disposed in spaced parallel relation the spindie, a rod mounted for slidable movement in the boss, a set screw threadedly mounted in the boss for optionally bearing against said rod to hold the rod in any 9 desired position of lengthwise adjustment within the limits of its slidable movement whereby the rod, when the set screw is tightened, will move to and fro with the carriage, a control switch electrically connected with the motor and having a switch-actuating element interposed in the path of the rod, and an inclined plate rigidly mounted at one end on the housing and having a rockable portion extending over the switch actuating element so as to be interposed between the switch actuating element and the rod whereby to stop the motor when the rod engages the plate at a selected point in the path of movement of the carriage in one direction.

HARRY B. BARRETT.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Porter Aug. 29, 1916 Neville Aug. 19, 1924 Bath Dec. 18, 1928 Walker Aug. 11, 1931 Waddel Aug. 25, 1931 Shippy Aug. 23, 1932 Hutto July 4, 1933 Groene July 19, 1938 Renholdt Nov. 28, 1939 Huenlich Feb. 11, 1941 Blazek Sept. 80, 1941 0158011 Jan. 7, 1945 Brooking Jan. 30, 1945 Koenig Jan. 17, 1950 

